Coffee filter and method of making same

ABSTRACT

A filter for brewing coffee or the like is formed of a sheet of paper folded along a line parallel to and slightly displaced from one axis of the sheet to form two sections, one larger than the other and then refolded about an axis transverse to the first axis to form four layers with the two sides of the larger segment abutting one another and sandwiched between the folded sides of the smaller segment. The filter may be easily opened by grasping an outer sheet and the remaining three sheets at their extending edge. The filter is made from an elongated web of filter paper by first trimming the edges of the web in a regular pattern which is not symmetrical with respect to the center line of the web, next folding along the longitudinal center line, then refolding the folded web along a plurality of regularly spaced lines transverse to the longitudinal center line and then cutting the folded stacked sections along a line parallel to and intermediate the folded edges.

United States Patent [191.

[111 3,800,954 Lampcov Apr. 2, 1974 COFFEE FILTER AND METHOD OF Primary Examine F-S amih N. Zahama MAKING SAME Harold Lampcov, Oak Park, Mich.

Assignee: Star Filter Company, Livonia, Mich.

Filed: May 3, 1972 App]. No.: 249,993

Inventor:

U.S. Cl. 210/497, 93/84 R Int. Cl B0lj 23/28 Field of Search 210/470, 474, 477, 483, 210/497; D44/29 K, 26 B; D7/47, 68, 129; 99/77.l; 156/204, 207, 226, 227, 250;

References Cited UNITED STATES PATENTS 10/1966 Manheim D74/26 B 11/1971 Cowen l6l/ll2X 5/1935 Monschein.... 210/497 X 11/1954 Schlumbohm. D44/26 B 3/1971 Whelan 210/497 4/1969 .Welin-Berger.. 210/477 X 5/1969 Honsel 210/477 X Assistant ExaminerF. F. Calvetti Attorney, Agent, or Firm-Fisher, Krass, Young &

Gerhardt [57] ABSTRACT A filter for brewing coffee or the like is formed of a sheet of paper folded along a line parallel to and slightly displaced from one axis of the sheet to form two sections, one larger than the other and then refolded about an axis transverse to the first axis to form four layers with the two sides of the larger segment abutting one another and sandwiched between the folded sides of the smaller segment. The filter may be easily opened by grasping an outer sheet and the remaining three sheets at their extending edge. The filter is made from an elongated web of filter paper by first trimming the edges of the web in a regular pattern which is not symmetrical with respect to the center line of the web, next folding'along the longitudinal center line, then refolding the folded web along a plurality of regularly spaced lines transverse to the longitudinal center line and then cutting the folded stacked sections along a line parallel to and intermediate the folded edges.

8 Claims, 8 Drawing Figures PATENTED R 2 mum:

l COFFEE FILTER AND METHOD OF MAKING SAME FIELD OF THE INVENTION This invention relates to a filter for infusing coffee into a hot liquid which consists of a sheet of paper folded and refolded so as to form quadrant sections,

and to a method of forming said filters from an elongated web.

BACKGROUND OF THE INVENTION Filters formed of paper, cloth, or other fluid pervious materials are commonly employed in connection with apparatus for infusing liquids with coffee, tea and similar potable materials. The material is supported on the filter and the fluid, usually heated, is passed through the material and filter either under pressure or the force of gravity. These filters are in common use in connection with percolator and dripolator coffee making apparatus as well as apparatus wherein heated water is simply poured over the coffee-contained in a filter.

One common form of such filter consists ofa circular or rectangular sheet folded and then refolded so as to form four identical quadrants. The free edge of one of the quadrants may be separated from the other three quadrants to form a pocket for the receipt of the coffee. One difficulty encountered in connection with the use of filters of. this type is the difficulty of separating the free edges of the folded filters so that three layers abut one another and the fourth layer is separated from them to form the pocket. If the filter is separated between the two middle sheets, no pocket is formed, but the person using the filter may not notice this and pour coffee into the filter only to have it pass through. This apparently occurs frequently enough to appreciably affeet the sales of such filters.

SUMMARY OF THE PRESENT INVENTION from an axis of symmetry, or substantial symmetry, of

the blank so as to form two sections, one slightly larger than the other so that the free edges of the two halves do not coincide. The blank is then refolded about an axis'of symmetry normal to the first axis to form four quadrants, two of which are larger than the other two. This refold is made in such a manner that the two larger quadrants abut one another. The free edge of the quadrant folded filter consists of the edges of the two shorter, outer sheets and the free edges of the two longer inner sheets projecting beyond the outer sheets.

In unfolding the filter, either one of the outer sheets may be pulled away from the remaining sections to form a pocket. With such a construction it is difficult to open the filter incorrectly by separating the pair of middle sections since their edges coincide along one another.

The present invention further contemplates a method and apparatus for manufacturing filters of the broad double fold type and more particularly filters formed in accordance with the present invention. To form such filters, an elongated webbing of filter paper having a width equal to the developed length of the paper along the second fold is first passed over a roll die to trim both of its opposed edges. The trimmed web is then passed over a folding head to create a longitudinal fold in the web so that the two sides of the web overlay one another with one edge extending beyond the other. If the trimming operation is formed symmetrically on both sides of the web, this folding operation is done along a line slightly displaced from the longitudinal center line of the web. If the trimming operation is asymmetrical, the longitudinal fold is made along the longitudinal center line of the web. The web is then repeatedly folded, in zig-zag manner, about equally spaced lines transverse to the longitudinal axis to form a stack of folded sections. The distance between these transverse fold lines is equal to the developed length of the resultant filter along the first fold line. Next, the stack of folded sections is cut along a transverse line midway between the transverse fold lines, as by a saw, in order to form stacks of finished separated filters.

The processing is thus continuous and in-line and requires no handling of the filter materials once they are cut off from the web.

Other objects, advantages and applications of the present invention will be made apparent by the following description of a preferred embodiment of the invention. The description makes reference to the accompanying drawings in which:

FIG. 1 is a plan view of a blank for forming a first embodiment of a filter embodying the present invention;

FIG. 2 is a plan view of the folded filter formed from the blank of FIG. 1;

FIG. 3 is a plan view of a second form of filter embodying the present application;

FIG. 4 is a plan view of the folded filter formed from the blank of FIG. 3;

FIG. 5 is a elevation view of the filter of FIG. 4;

FIG. 6 is a schematic view illustrating the method of forming filters in accordance with the present inventron;

FIG. 7 is a schematic view of apparatus used to form filters in accordance with the present invention; and

FIG. 8 is a view of a filter formed with the apparatus of FIG. 7.

Filters in accordance with the present invention may be formed of blanks of symmetrical or substantially symmetrical shape. FIG. 1 illustrates a circular blank 10 from which a first embodiment of the filter is formed. Blank 10 preferably consists of a fluid pervious filter paper of cotton but other pervious sheet materials can be used with the invention. To form a filter, the sheet is first folded through about a line 12 extending parallel to and slightly separated from any diametric bisector of the blank 12 such as the dotted line designated 14. The result is a pair of folded sections, one of which is slightly larger than the other so that their free edges do not coincide.

The folded section thus formed is then refolded along a diametric line 16 extending normally to the line 12. This fold is made in such a way that the two halves of the larger section produced by the fold along the line 12 lie in abutment to one another. The. result is the triangular shaped filter element 18 illustrated in FIG. 2. The free edges of the two interior sections 20 extend beyond the free edges of the two outer sections 22. This filter may be opened to substantially conical form by separating either of the outer edges 22 from the remaining three edges to form a closed filter suitable for the reception of coffee, tea or other materials or for other uses to which such filters may be put.

FIG. 3 illustrates a square blank 24 which may be folded to form a second embodiment of the filter. The first fold is made along a line 26 slightly displaced, as by one-half inch, from one central axis 28 of the sheet 24. The second fold is then made along a line 30 forming the other central axis of the sheet 24 so that the two sections containing the line 28 (the larger sections) lie abutting one another. The finished filter 32 consists of a quarter folded sheet with the two free edges of the inner portions, along one side, as at 34, extending beyond the free edge 36 of the other portion.

FIG. 6 schematically illustrates a method of forming web of sheet material. This apparatus is particularly useful in forming the filters of the present invention.

As illustrated in'the plan view of FIG. 6 a web of filter material 38 is first trimmed on its opposed edges 40 and 42 to form a series of regular segments having the shape of the finished filter as laid out. Next the web is folded along a longitudinal line as at numeral 44. When conventional quarter-fold filters are being formed, the line on which the fold 44 is made will be the center line of the web. When filters are formed in accordance with the present invention by this method, the fold line may be slightly displaced from the center line of the web, or alternatively the fold may be on the center line and the two side trims 40 and 42 may be made in a slightly asymmetrical manner so as to trim more from one side than. the other. By either of these methods, the web is folded into two sections, one of which is slightly larger than the other. I

The trimmed and folded web is then folded and refolded in a zig-zag pattern as at 46. The zig-zag fold lines are made along lines transverse of the first fold.

The stack of connected filters thus produced is then separated by cutting the stack along a line parallel to and midway between the transverse zig-zag fold lines that form separate sections.

FIG. 8 illustrates a filter 50 formed by the method illustrated in FIG. 6 wherein one of the egde trims 40 is larger than'the other edge trim 42. The resultant filter 50 has a center section 52, the free edge-of which extends beyond the free edge of the two outer sheets along only a portion of its free length. This filter is easily opened to form a pocket in the same manner as the filters of FIGS. 1 and 3. FIG. 7 schematically illustrates apparatus which might be used to implement the method of FIG. 6. The web 38 is trimmed along its edges by a pair of roller cutting dies 54. The longitudinal fold at 44 is made by a conventional folding head 56. A zig-zag folder 58 of the type used to make quarter a multiplicity of quarter fold filters froman elongated A v v .4 folded napkins is schematically illustrated. The cut to separate the napkinsmay be made by" circular saws schematically illustrated at 60.

Having thus described my invention, I claim:

1. A filter of the type described, comprising a sheet of filter paper first folded along a line so as to form a pair of sections of similar shape, one of which has a greater dimension than the other along an axis normal to said fold line, and then refolded along a second line transverse to said first fold line so that the folded parts of said section having the greater dimension abut one another to form a four-layer section wherein the free edges of the two center layers extend beyond the free 4. The filter of claim 1 wherein said second line bisects the section formed by the first fold.

5. A filter of the type described, comprising a sheet of symmetrical filter paper first folded along the line parallel to and displaced from an axis of symmetry of said sheet to form a pair of sections of similar shape, one of which has a greater dimension than the other along an axis normal to said fold line, and then refolded along a second line transverse to said first line, said second line constituting a line of symmetry of said original sheet, so as to form a four layer section wherein at least a'por'tion of the free edges of the two center layers extend beyond the free edges of the two outer layers so as to allow the filter to be opened by grasping the free edge of one of the outer layers and the free edges of the two center layers.

6. The filter of claim 5 wherein said sheet is circular.

7. The method of making filters comprising the steps of: trimming the opposed edges of a web of filter paper in a manner which is asymmetrical relative to the longitudinal axis of the web; folding the web along a longitudinal line so as to form a pair of sections, one of which has a greater dimension than the other along an axis normal to said fold line; zig-zag folding the formed web about a plurality of transverse lines; and cutting the web along a line parallel to and intermediate said transverse lines to form a plurality of filters folded along a first line, then refolded along a second line transverse to said first line.

8. The method of claim 7 wherein the longitudinal line about which the web is folded is displaced from the longitudinal axis of the web. 

1. A filter of the type described, comprising a sheet of filter paper first folded along a line so as to form a pair of sections of similar shape, one of which has a greater dimension than the other along an axis normal to said fold line, and then refolded along a second line transverse to said first fold line so that the folded parts of said section having the greater dimension abut one another to form a four-layer section wherein the free edges of the two center layers extend beyond the free edges of the two outer layers aLong at least a portion of the perimeter.
 2. The filter of claim 1, wherein the original sheet is substantially symmetrical about a pair of perpendicular axes and the first fold is made along a line extending parallel to and displaced from one of said axes.
 3. The filter of claim 1 wherein said sheet is circular so that the finished filter is in four quadrant sections.
 4. The filter of claim 1 wherein said second line bisects the section formed by the first fold.
 5. A filter of the type described, comprising a sheet of symmetrical filter paper first folded along the line parallel to and displaced from an axis of symmetry of said sheet to form a pair of sections of similar shape, one of which has a greater dimension than the other along an axis normal to said fold line, and then refolded along a second line transverse to said first line, said second line constituting a line of symmetry of said original sheet, so as to form a four layer section wherein at least a portion of the free edges of the two center layers extend beyond the free edges of the two outer layers so as to allow the filter to be opened by grasping the free edge of one of the outer layers and the free edges of the two center layers.
 6. The filter of claim 5 wherein said sheet is circular.
 7. The method of making filters comprising the steps of: trimming the opposed edges of a web of filter paper in a manner which is asymmetrical relative to the longitudinal axis of the web; folding the web along a longitudinal line so as to form a pair of sections, one of which has a greater dimension than the other along an axis normal to said fold line; zig-zag folding the formed web about a plurality of transverse lines; and cutting the web along a line parallel to and intermediate said transverse lines to form a plurality of filters folded along a first line, then refolded along a second line transverse to said first line.
 8. The method of claim 7 wherein the longitudinal line about which the web is folded is displaced from the longitudinal axis of the web. 